Athel pine (Tamarix aphylla) NT Weed Risk Assessment Technical Report
January 2014
www.nt.gov.au/weeds
Athel pine Tamarix aphylla Please cite this report as: Department of Land Resource Management (2014). Athel pine (Tamarix aphylla) NT Weed Risk Assessment Technical Report, Department of Land Resource Management, Darwin.
ISBN: 978-1-74350-050-7
Acknowledgments The NT Weed Risk Management (WRM) System was jointly developed by Charles Darwin University (CDU) and the Weed Management Branch, Department of Land Resource Management (DLRM); our thanks to Samantha Setterfield, Natalie Rossiter-Rachor and Michael Douglas at CDU. Project funding for the development of the NT WRM System, obtained by Keith Ferdinands and Samantha Setterfield, came from the Natural Heritage Trust. Our thanks to the NT WRM Reference Group for their assistance in building the NT WRM System and the NT WRM Committee for their role in building the system and their ongoing role in weed risk assessments.
Cover photo (top): Cultivated athel pines growing near buildings. Cover photo (bottom): Athel pine infestation along the Finke River, NT.
Final report compiled January 2014. Edited by Louis Elliott, Department of Land Resource Management.
NOTE: Online resources are available at https://nt.gov.au/environment/weeds/list-of- declared-weeds-in-the-nt/athel-pine which provide information about the NT Weed Risk Management System including an explanation of the scoring system, a fact sheet and user guide, a map of the NT weed management regions and FAQs.
Weed Management Branch contacts For more information or advice in relation to the identification, management or monitoring of weeds please contact the Weed Management Branch: Phone: (08) 8999 4567 Email: [email protected] Website: http://www.nt.gov.au/weeds
The NT Herbarium can also provide plant identification advice Phone: (08) 8999 4516
Rangelands Division Department of Land Resource Management PO Box 496 Palmerston NT 0831
© Northern Territory of Australia, 2014 This product and all material forming part of it is copyright belonging to the Northern Territory of Australia. You may use this material for your personal, non-commercial use or use it with your organisation for non-commercial purposes provided that an appropriate acknowledgement is made and the material is not altered in any way. Subject to the fair dealing provisions of the Copyright Act 1968 you must not make any other use of this product (including copying or reproducing it or part of it in any way) unless you have the written permission of the Northern Territory of Australia to do so. 2 www.nt.gov.au/weeds
Athel pine Tamarix aphylla Weed risk and Feasibility of Control results
Table 1. Weed Risk and Feasibility of Control (FOC) results for athel pine (Tamarix aphylla). Weed Risk is calculated for the whole of the Northern Territory; FOC is calculated by Weed Management Region. Maximum score for Weed Risk and FOC is 1000. Each has three sections (A, B, C), with section scores expressed as a percentage. Weed Risk (NT)
Band Very high Score 412 Note: For an explanation of how the Weed Risk and Feasibility of Control scores and bands are calculated, A. Invasiveness (%) 83 and for the Northern Territory Weed Management B. Impacts (%) 74 Regions, refer to www.nt.gov.au/weeds/risk. C. Potential distribution (%) 67 Feasibility of Control (by region)
Weed Management Region Darwin Katherine Tennant Creek Alice Springs Band - - High Medium Score - - 251 125 A. # Control costs (%) - - 55 55
B. ## Current distribution (%) - - 100 50
C. Persistence (%) - - 46 46 # A high score indicates low control costs and contributes to a high Feasibility of Control. ## A high score indicates a restricted distribution and contributes to a high Feasibility of Control.
Table 2. Broad management response recommended for athel pine (Tamarix aphylla) by Weed Management Region, according to Weed Risk and Feasibility of Control assessments. Feasibility of Control
Very high–High Medium–Low
Prevent movement; regional eradication; Targeted control (including biocontrol)/protect Very high contain regional spread; protect priority sites priority sites
Prevent movement; contain regional spread; High protect priority sites Targeted control
Medium Targeted control; improve general weed Improve general weed management management; monitor; protect priority sites
Low Monitor; assist interested parties Assist interested parties
Tennant Creek Region Alice Springs Region
www.nt.gov.au/weeds Athel pine Tamarix aphylla 3
Background information Taxon Tamarix aphylla Synonyms Tamarix articulata, Thuja aphylla Common name Athel pine Other names Tamarisk, saltcedar, athel tree Family Tamaricaceae (tamarisk family) Lifeform Tree Environment Terrestrial Origin Northern Africa, the Arabian Peninsular, Iran and India. Legislation Declared in all other Australian states and territories. Declared Class A and Class B in different parts of the Northern Territory. The NT declaration zones for athel pine are available at: www.nt.gov.au/weeds/find/athelpine.
Description Large, spreading tree up to 15 m tall. Athel pine is not a true conifer or pine, but its pendulous needles and branches give it the appearance of one. Salt secreting glands in the needles create a whitish coating giving the tree foliage a silvery grey appearance. Small, white and pink flowers occur in dense racemes. Habitat Dominates sandy riparian habitats in the arid zone. In the Northern Territory, it forms monospecific stands along rivers and adjacent fringing woodlands in the arid zone. It is spread by wind and floodwaters, and is able to establish on sandy soils free of other vegetation. Distribution There are large infestations present in South Australia, New South Wales, Queensland and Western Australia. In the Northern Territory athel pine is mainly found in the central region, where it was extensively planted in Aboriginal communities and at homesteads, bores and roadhouses as far north as the Barkly region. Extensive stands of athel pine are found on the Finke River system south of Alice Springs. Other Athel pine is recognised as a Weed of National Significance. Athel pine is also a significant invasive species in southern USA.
Current situation in the NT In the Northern Territory (NT) athel pine is well established in the Finke River, this being the largest naturalised infestation in Australia. Infestations outside this core area, such as those found in Walker and Karinga Creeks, are smaller and of lower density, and as such have been prioritised for management. Historical and amenity plantings of athel pine are found throughout the southern region of the Territory. As these present potential for spread, their control and removal is also considered a management priority.
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Athel pine Tamarix aphylla Summary of Weed Risk and Feasibility of Control Weed RIsk A. Invasiveness: Intentionally introduced into Australia and widely planted for shade. Current infestations originate from trees planted around homesteads and communities. Seed viability is moderate (c. 22%), but a single tree is capable of producing enormous quantities of tiny seed (c. 500 000) which are principally spread by floodwaters. A major dispersal event occurred in the NT with the flood of 1974, with floods in later years aiding further establishment. It is also able to spread vegetatively—broken stem fragments can take root and are also spread by floods. People may continue to accidentally spread athel pine with heavy machinary such as graders. B. Impact: Forms monocultures which displace native vegetation, particularly the iconic river red gums (Eucalyptus camuldulensis) and coolibah (Eucalyptus microtheca) in central Australia. Athel pine extracts salt from the soil, causing salination affecting plant growth up to 50 m away. It lowers the water table, dry up waterholes, adds to sedimentation rates and can change the course of rivers. Only salt-tolerant herbs or grasses can grow under athel pine, so it reduces grazing area. Native birds, reptiles and insects are negatively impacted—athel pine flowers have no nectar, the trees do not provide hollows for nesting, and it is a poor source of food for invertebrates. A threatened species of brushtail possum is impacted. C. Potential distribution: Wide native and introduced range throughout arid and semi-arid zone, surviving in areas with rainfall as low as 100 mm/year. The climate for optimum growth is probably 350–500 mm/year. Particularly suitable vegetation types in the NT are arid and semi-arid riparian and wetland areas, due to dispersal by floodwaters and the close proximity of groundwater.
Feasibility of Control A. Control costs Moderate. Athel pine is readily identifiable and infestations are generally accessible for treatment. However, the tree does not translocate chemical well. Chemical and labour costs are very high, especially for large infestations. B. Current distribution (NT) Large stands of athel pine exist on the Finke River system in the Alice Springs Region. In other parts of the arid and semi-arid NT, infestations tend to isolated. In these areas, isolated trees planted for amenity purposes continue to exist. C. Persistence Moderate. Seeds remain viable for a only a few weeks. However vegetative propagules can propagate even when there is no seed. The tree can live for at least several decades.
General Management Recommendations Refer to the Weed Management Plan for Athel Pine (Tamarix aphylla). This can be found at www.nt.gov.au/weeds/find/athelpine.
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www.nt.gov.au/weeds Athel pine Tamarix aphylla
Weed Risk Assessment - Determinations
A. INVASIVENESS Determination
A1. What is the ability of the plant to establish amongst intact native environments? Very high A2. What is the reproductive ability of the plant? a) Time to seeding 2-3 years b) Annual production of viable seed per sq m or /plant High c) Vegetative reproduction
Frequent A3. Do propagules of the plant have properties that allow them to be dispersed long-distance by natural means? a) Flying animals (birds, bats) Don't know b) Other wild animals Don't know c) Water Yes d) Wind Yes A4. How likely is long-distance dispersal by human means? a) Deliberate spread by people Unlikely b) Accidentally by people and vehicles Occasional c) Contaminated produce Unlikely d) Domestic/farm animals Occasional B. IMPACTS
B1. What is the plants competitive potential? High B2. What is the plant’s potential to modify the existing fire behaviour and alter the fire regime? Some potential B3. What is the plant’s potential to restrict the physical movement of people, animals, vehicles, machinery and/or water? High B4. What is the plant’s potential to negatively affect the health of animals and/or people? None B5. Does the plant potentially have negative effects on natural and cultural values? a) reducing habitat quality for native animals High b) threatened species or communities One c) sites of natural significance More than 1 B6. Is the plant presumed to have negative effects on environmental health? a) soil chemistry/stability Yes b) water quality Yes c) hydrology Yes C. POTENTIAL DISTRIBUTION
C1. What is the CLIMATE suitability score (which indicates the proportion of the NT environment that is suitable for the plant)? 8.8 C2. How many broad habitat types in the NT will the plant potentially naturalise in (up to 5) ? Two C3. What is the potential of the plant to occur throughout its favoured habitat in the NT (from those identified in question 2)? Some
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Feasibility Of Control - Determinations
A. CONTROL COSTS Darwin Region Katherine Region Tennant Ck Region Alice Springs Region A1. How detectable is the weed? a) Distinguishing features Always distinct Always distinct 4-8 months 4-8 months b) Active growth period > 2 m > 2 m c) Height at maturity
A2. What is general accessibility of infestations at the optimum treatment time?
Medium Medium
A3. How expensive is control of the weed in the first year of targeted control, for an infestation that has reached maximum weed density? Very High Very High a) Chemical cost Very High Very High b) Labour costs Low Low c) Equipment costs
A4. What is the general community perception of this week within the region?
High High
B. CURRENT DISTRIBUTION
B1. What is the current pattern of the weed’s distribution across the weed's range in the NT?
Restricted Restricted
C. PERSISTENCE
C1. How long will it take to reach the maintenance period? The maintenance period is reached when there is no further recruitment from the original infestation, although monitoring and follow up may still be required.
Medium Medium
C2. What is the minimum time period for reproduction of sexual or vegetative propagules?
<1 year <1 year C3. What is the maximum longevity of sexual or vegetative propagules?
>5 years >5 years
C4. What is the threat of reinfestation from outside the region?
a) Long-distance dispersal by natural means
Frequent Frequent
b) Long-distance dispersal by human means
Occasional Occasional
www.nt.gov.au/weeds Athel pine Tamarix aphylla
Figure 1. Global records of athel pine (Tamarix aphylla). Source: Global Biodiversity Information Facility and Australian Virtual Herbarium (2007).
Figure 2. Potential distribution of athel pine (Tamarix aphylla) in Australia using CLIMATCH. Areas of suitable climate are indicated by a climatic suitability score of 7 or above out of 10. Source: NT Weed Management Branch 2010.
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Weed Risk Assessment - Evidence Used
A INVASIVENESS
A1 What is the ability of the plant to establish amongst intact native environments?
The established trees [on the Finke River] now tend to form dense, almost Griffin et al. (1989) monospecific stands, which appear to displace the native river gum (Eucalyptus camaldulensis) from parts of the river. Csurhes (2008) Dominates sandy riparian habitats in arid areas such as Finke River and excludes all other vegetation. In places, river red gums (Eucalyptus camuldulensis) an icon of central Australia, have been replaced by Athel Pine.
In the Finke River, the infestation of Athel pine ..extends into the dense Duguid et al. (2002) fringing Coolabah woodlands. The infestation has now reached the Finke Floodout forest; an area of very dense Coolabah (Eucalyptus coolabah subsp. arida) and Cooba (Acacia salicina) woodland/forest. Along the Finke River it has formed many monospecific stands at the expense Parsons & Cuthbertson of the river red gum, Eucalyptus camaldulensis Dehnh., and the coolibah, (1992) Eucalyptus microtheca F. Muell., considerably reducing the available grazing area. Over the past 18 years Athel pine has become established along several hundred Fuller (1993b) kilometres of the Finke River in the NT. Seedlings seem only to establish on sandy soils that are free of vegetation. Csurhes (2008)
In the Lake Mead recreational area (Nevada, USA) Tamarix aphylla has spread Walker et al. (2006) from 4 large trees in 1982 to over >5000 individuals in the same area of the park in 2006. A2a Reproductive ability: Time to seeding?
The first flowers appear in about the third year, and annually thereafter, in Parsons & Cuthbertson summer. (1992)
A2b Reproductive ability: Annual production of viable seed per square meter or per plant?
Athel pine flowers and produces many seeds, but most of the seeds are sterile. Tesky (1992)
Seed viability is moderate (ca. 22% under best conditions) and seed Dudley (2004) production period [in America] is fairly restricted, but because millions of seeds can be produced, under the right conditions the potential for invasion is theoretically very high T. aphylla produces a large number of seeds, i.e. about 500,000 seeds/year from CAB International (2000) a single tree. The seeds are minute, about 1000 per gram. 500,000 seeds per year from a single tree X 22% viability = 11,0000 viable seeds per year from a single tree.
A2c Reproductive ability: Vegetative reproduction? In their native habitat, propagation is assumed to be mostly vegetative, although Griffin et al. (1989) establishment from seeds after summer rains has been reported. Its main method of propagation is vegetative. It sprouts from the root crown or Tesky (1992) forms adventitious roots from submerged, broken or buried stems. Athel pine reproduces from broken stem fragments as well as from seeds. Csurhes (2008) Vegetative reproduction is particularly successful when branches are broken up by floodwaters and carried downstream.
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Weed Risk Assessment - Evidence Used
A3a Propagule dispersal: Flying animals (birds, bats) Seeds are spread . . . by birds. Parsons & Cuthbertson (1992)
A3b Propagule dispersal: Other wild animals Seeds are spread . . . by animals. Parsons & Cuthbertson (1992)
A3c Propagule dispersal: Water
Major flows in the Finke River in 1974 dispersed seed along its entire length, Fuller (1993b) and the wet conditions that followed were ideal for seed establishment. Further floods in 1983 and 1984 enabled more Athel pine to establish, from seed and vegetable matter, probably from those trees established in the 1974 floods.
Seeds are spread principally by floodwaters . . . Parsons & Cuthbertson (1992) Tesky (1992) It can colonise disturbed areas by broken limbs carried by water.
A3d Propagule dispersal: Wind
Waisel (1960) The minute seeds [of Tamarix aphylla] are furnished with a pappus, making them fit for long distance dissemination.
Seeds are small enough to be carried over short distances by the wind. Csurhes (2008)
Griffin et al. (1989) Seeds have a pappus, making them suitable for wind transportation, but they are viable for only a few weeks.
Fruit is small, sessile, capsule like and ripens in the cold season. The capsules CAB International (2000) contain minute seeds. Ripe capsules turn brown and open up gradually to allow the minute seeds to be dispersed by the wind.
A4a Human dispersal: Deliberate spread by people
Athel pine was introduced into Australia to provide shelter against wind and Csurhes (2008) sun and for use as an ornamental in the arid and semi-arid zone. It was planted extensively around Broken Hill and Whyalla in the 1930’s and 40’s and soon after in other states, particularly around homesteads, stock yards, bores and other hot, exposed sites on grazing properties and towns. All infestations originated from trees planted around homesteads and communities Fuller (1993b) for shade.
A4b Human dispersal: Accidentally by people and vehicles There is evidence to suggest that Athel Pine is spread accidentally by people, C. Brown [NT Weed particularly via vegetative material adhering to heavy machinery such as earth Management Branch, Alice moving equipment, road graders etc. Springs] 2007, pers. comm.
A4c Human dispersal: Contaminated produce It would not be spread by contaminated produce. C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.
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Weed Risk Assessment - Evidence Used
A4d Human dispersal: Domestic/farm animals It is possible that it could be spread by domestic and feral herbivores. C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.
B IMPACTS
B1 What is the plant's competitive potential? Dominates sandy riparian habitats in arid areas such as Finke River and excludes Csurhes (2008) all other vegetation. Along the Finke River it has formed many monospecific stands at the expense Parsons & Cuthbertson of the river red gum (Eucalyptus camaldulensis Dehnh.), and the coolibah (1992) (Eucalyptus microtheca F. Muell), considerably reducing the available grazing area. Few native herbs persist under the dense infestations. Fuller (1993b) B2 What is the plant's potential to modify the existing fire behaviour and alter the fire regime?
Because they are drought tolerant and fire resistant, athel pines decrease the Commonwealth frequency of fires and alter vegetation structure. Department of Environment and Heritage (2003) Athel pines do not allow fire to pass through an area and as a consequence Csurhes (2008) natural fire regimes are altered. This can affect the regeneration of many native plant species. T. aphylla is fire-hardy and is a useful species to plant as a firebreak. The salt CAB International (2000) drip from branches becomes moist due to its hygroscopic nature and suppresses other inflammable vegetation. Moreover, the leaf litter is too saline to burn. It can be grown in 30 m wide strips to check the spread of wildfires common in dry regions. T. aphylla is not known to increase fire risks. Dudley (2004)
The high ash (30-40%) and salt content of its foliage make it hard to burn even Tesky (1992) when dry. B3 What is the plant's potential to restrict the physical movement of people, animals, vehicles, machinery and/or water?
Presence of the trees may alter the course of rivers. Fuller (1993b)
Athel pine increases soil sedimentation in arid rivers systems. Humphries et al. (1991) Griffin et al. (1989) Increases in the density of tamarisks may well alter the river’s course and increase sedimentation rates by trapping and stabilising sediments during floods.
Extensive, old stands lower the water table and cause water holes to dry up. Csurhes (2008) B4 What is the plant's potential to negatively affect the health of animals and/or people?
Tamarix spp. are relatively unpalatable to most classes of livestock and Tesky (1992) wildlife. Athel tamarisk foliage contains phenolic acids which may prevent herbivory.
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Weed Risk Assessment - Evidence Used
B5a Natural & cultural values: Reducing habitat quality for native animals
Dominates sandy riparian habitats in arid areas such as Finke River and Csurhes (2008) excludes all other vegetation. In places, river red gums (Eucalyptus camuldulensis) an icon of central Australia, have been replaced by Athel Pine. Unlike eucalypts, athel pines do not provide nesting hollows or food for native wildlife.
Griffin et al. (1989) The displacement of eucalypts by tamarisks has resulted in dominance of the ground vegetation by a relatively few species or introduced or salt-tolerant plants.
Fewer birds occurred in the area invaded by tamarisks. Birds could find Griffin et al. (1989) tamarisks unsuitable as they provide only tiny flowers which presumably attract few insects and no nectarivorus birds; their foliage is devoid of herbivorous species; and, tamarisks probably suppress ground-dwelling insects because of depauperate litter fauna. Fewer herbs and forbs grow through the litter to provide substrate for invertebrates. In addition, holenesting birds probably decline in abundance near tamarisk infestations during breeding periods, due to the absence of tree-hollows in tamarisk stands. Fewer reptiles occurred in the area invaded by tamarisks. Reptiles could find Griffin et al. (1989) tamarisks less suitable as: the litter beneath tamarisks appeared to contain sparse populations of litter invertebrates; and tamarisk deposited few logs or dead branches on the ground, and those on the ground did not have the same thick persistent bark of the eucalypts that encourages colonization by reptiles.
B5b Natural & cultural values: Threatened species of communities One threatened species affected, common brush tail possum. J. Woinarski [NT Biodiversity Conservation] 2007, pers. comm.
Athel Pine does have a significant impact on the natural values of inland C. Brown [NT Weed waterways such as the Finke River as it can dominate large sections of the river Management Branch, Alice channel excluding native river red gums and coolabahs. These inland riverine Springs] 2007, pers. comm. areas form significant breeding and refuge areas for native wildlife.
Burbidge et al. (1988) In central Australia, the common brushtail possum now occupies riverine Kerle et al. (1992) habitat that is close to rocky outcrops and moist gullies within the ranges or rocky slopes (Kerle et al. 1992). This habitat occurs on various geological Pavey (2006) substrates but is characterized by a diverse association of fire-sensitive plant species. Its former habitat in central Australia included river systems supporting large eucalypts, coolibah claypans and spinifex grasslands with a shrubby overstorey (Burbidge et al. 1988).
B5c Natural & cultural values: Sites of natural and cultural significance
Duguid et al. (2002) The Finke and several other water courses are listed as nationally significant J. Woinarski [NT wetlands and river red gums are characteristic of these sites. Biodiversity Conservation] 2007, pers. comm.
B6a Environmental health: Soil chemistry/stability Their extensive roots also extract all soluble salts from the soil; these are CAB International (2006) excreted through the glands in the leaves onto the top of the soil in the form of litter or 'tears', thus causing salinisation of top soil even in non-saline areas, reducing the growth of nearby plants up to a distance of 50 m. Athel pine tolerates saline water and exudes large quantities of salt through its Csurhes (2008) leaves, leading to increasing levels of salinity in surrounding soil.
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Weed Risk Assessment - Evidence Used
Tamarisk tolerates saline water and exudes large quantities of salt through its Berry (1970) leaves; the salt concentration on the foliage may be up to 50 times that in the root water supply. Leaf litter from T. aphylla can significantly increase soluble salts in the soil Litwak (1957) surface, with the mean values under the canopy about twice or three times as high as out in the open. Fig. 1 Mean of total soluble salts (in parts per million) in soil under the canopy of Tamarix aphylla and in the open (from Litwak, 1957). Depth Under canopy In open Difference 0 cm 1201 ± 345 480 ± 120 721*± 299 40 cm 1198 ± 216 512 ± 102 678**± 250 80 cm 859 ± 187 490 ± 78 368**± 57 * Significant at 0.05, ** Significant at 0.01 The change in soil composition was also affected by the age of the trees, with total soluble salts highest under large mature trees. B6b Environmental health: Water quality
Presence of the trees may increase sedimentation rates. Fuller (1993b)
Griffin et al. (1989) Exotic tamarisk trees have become established along several hundred kilometres of the Finke River, the largest river system in arid central Australia. Establishment appears to have deposited large quantities of sediment on the levees.
Humphries et al. (1991) Athel pine increases soil sedimentation in arid rivers systems.
B6c Environmental health: Hydrology
Csurhes (2008) Athel pine is a hydrophyte, which means it has specialised roots that draw water from deep underground. It uses large quantities of water and dense stands can have significant impacts on underground water tables.
Tamarix aphylla is known to lower ground water tables. Csurhes & Edwards (1998)
Csurhes (2008) Extensive, old stands lower the water table and cause water holes to dry up.
C POTENTIAL DISTRIBUTION C1 What is the CLIMATE suitability score (which indicates the proportion of the NT environment that is suitable for the plant)?
The native range of T. aphylla extends over the Middle East, North, East and CAB International (2000) Central Africa, and parts of West and South Asia. The species is thought to have originated in the Central Sahara, from where it spread to Pakistan, India, Afghanistan, the Middle East, Egypt and North Africa, as well as to Eritrea, Somalia, Kenya and Ethiopia. Waisel (1960) Tamarix aphylla has a very wide range of distribution in North Africa and in Western Asia…It is assumed to be indigenous in Morocco, Algeria, Tunisia, Central Sahara, Lybia, Egypt, Sudan, Israel, Trans-jordan, Syria, Iraq, Arabia, Yeman, Iran, Baluchistan, Sind and Punjab.
It is an aggressive, fast growing species which survives in areas where National Academy of annual rainfall is as low as 100 mm (optimum growth is probably 350-500 mm Sciences (1980) per annum). The CLIMATE model used by the NT Weed Management Branch predicts that NT Weed Management 88% of the NT is climatically suitable for athel pine (see Figure 1). Branch (2007)
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Weed Risk Assessment - Evidence Used
C2 How many broad vegetation types in the NT will the plant potentially naturalise in (up to 5) ?
The broad vegetation types that Tamarix aphylla will potentially naturalise in are: NT Weed Risk • Arid and semi-arid wetlands Management Committee • Arid riparian (2007) The favoured vegetation type is arid riparian. Rossiter-Rachor (2012)
Vegetation types: deserts; dry forests; dunes CAB International (2000) C3 What is the potential of the plant to occur throughout its favoured habitat in the NT (identified in question 2)?
Tamarix aphylla has the potential to occur through some of its favoured NT Weed Risk habitat. Management Committee (2007)
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Feasibility of Control - Evidence Used
A CONTROL COSTS
A1a Distinguishing features Csurhes & Edwards (1998) Tamarix aphylla (Athel pine) is a spreading tree reaching 10 m in height. The leaves are blue green and are similar in appearance to pine needles. Flowers are pinkish white and are arranged in racemes at the end of the branches.
Always distinct. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. A1b Active growth period Comm.
Active growth period 4-8 months (spring/summer). P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. A1c Height at maturity Comm. The height at maturity is >2m. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm. Tamarix aphylla (Athel pine) is a spreading tree reaching 10 m in height. Csurhes & Edwards (1998) A2 Is general accessibility of infestations at the optimum treatment time?
The general accessibility of infestations is Medium. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm. Medium (all work done with 4WD quadbikes). C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm. A3a Chemical cost
Chemical Costs: Medium Category ($250-$500/Ha). C. Brown [NT Weed Athel pine does not translocate chemical well Management Branch, Alice In the maximum density infestation of Athel pine (like has been on the Finke) Springs] 2007, pers. there would be large broken stems plants, as well as seedlings coming up. comm. Would need to use: • 4-5 L of access of Garlon/ha @ $70/L = 280-350 P. Jeffery, M. Fuller & G. • 1000L of diesel /ha @ $1.80/L McSkimming [weed control Therefore would cost $2080 - $2150 per hectare. contractors] 2007, pers. [Note: This would place Athel pine control in the Very High (>$500 /ha) Comm. chemical costs category]
A3b Labour costs
The labour costs for controlling a maximum density Athel pine infestation would P. Jeffery, M. Fuller & G. include people to do basal bark control, as well as spraying seedlings, and McSkimming [weed control someone operating the earthmoving equipment. [Note: This would place contractors] 2007, pers. Athel pine control in the Very high (>$500 /ha) labour costs category] Comm.
Labour Costs: High ($200-$500). C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.
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Feasibility of Control - Evidence Used
A3c Equipment costs C. Brown [NT Weed Equipment Costs: High (for dense stands of mature trees as requires bulldozer). Management Branch, Alice Springs] 2007, pers. comm. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm. A4 What is the general community perception of this weed within the region? The general community perception of Athel pine is High. Well known weed in P. Jeffery, M. Fuller & G. the Alice Springs region. McSkimming [weed control contractors] 2007, pers. Comm.
B CURRENT DISTRIBUTION
B1 What is the current pattern of the weed's distribution across the weed's range?
Athel pine’s distribution in the Alice Springs region is Scattered. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm.
In the Northern Territory athel pine is mainly found in the central region of the Department of Land Northern Territory, where it has been extensively planted on Aboriginal Resource Management communities and at homesteads, bores and roadhouses as far north as the Barkly (2014) region. Athel pine is well established in the Finke River.
C PERSISTENCE
C1 How long will it take to reach the maintenance period?
Medium. It is likely to take 2-5 years to reach the maintence period. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm.
C2 What is the minimum time period for reproduction of sexual or vegetative propagules?
The minimum time for reproduction is within 1 year. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm.
The first flowers appear in about the third year, and annually thereafter, in summer. Parsons & Cuthbertson (1992)
C3 What is the maximum longevity of sexual or vegetative propagules?
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Feasibility of Control - Evidence Used
Seed viability is moderate (ca. 22% under best conditions) and seed Dudley (2004) production period [in America] is fairly restricted, but because millions of seeds can be produced, under the right conditions the potential for invasion is theoretically very high.
Although a single tree can produced 500 000 seeds. The seed is short lived, lasting Griffin et al. (1989) only a few weeks.
About 60% of stem tissues produce new shoot/roots under greenhouse Brock (1994) conditions, while root cutting was less successful, producing only about 19% new shoot growth. [Note that this paper only refers to Tamarix spp.] Waisel (1960) T. aphylla cuttings lose their vitality after loosing one-third of their water content.
Tamarix aphylla can reproduce by seed, but most spread is via broken living plants Csurhes & Edwards (1998) that are transported in floodwaters. The maximum longevity of vegetative propagules is greater than five years. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm.
C4a Long-distance dispersal by natural means
Major flows in the Finke River in 1974 dispersed seed along its entire length, Fuller (1993b) and the wet conditions that followed were ideal for seed establishment. Further floods in 1983 and 1984 enabled more Athel pine to establish, from seed and vegetable matter, probably from those trees established in the 1974 floods.
Seeds are small enough to be carried over short distances by the wind. Csurhes (2008)
It can colonise disturbed areas by broken limbs carried by water. Tesky (1992)
Seeds are spread principally moved by floodwaters. Parsons & Cuthbertson (1992)
Seeds are spread . . . by animals Parsons & Cuthbertson (1992)
Long-distance dispersal of Athel pine by natural means is likely to be rare. P. Jeffery, M. Fuller & G. McSkimming [weed control contractors] 2007, pers. Comm. T. aphylla can reproduce by seed, but most spread is via broken living plants that Csurhes & Edwards (1998) are transported in floodwaters.
C4b Long-distance dispersal by human means C. Brown [NT Weed It would not be spread by contaminated produce but there is the possibility that it Management Branch, Alice could be spread by domestic and feral herbivores. Springs] 2007, pers. comm. P. Jeffery, M. Fuller & G. Long-distance dispersal of Athel pine by human means is likely to be rare McSkimming [weed control contractors] 2007, pers. Comm.
www.nt.gov.au/weeds 17 Athel pine Tamarix aphylla
Athel pine was introduced into Australia to provide shelter against wind and Csurhes (2008) sun and for use as an ornamental in the arid and semi-arid zone. It was planted extensively around Broken Hill and Whyalla in the 1930’s and 40’s and soon after in other states, particularly around homesteads, stock yards, bores and other hot, exposed sites on grazing properties and towns.
All infestations originated from trees planted around homesteads and communities Fuller (1993b) for shade. There is evidence to suggest that Athel Pine is spread accidentally by people, C. Brown [NT Weed particularly via vegetative material adhering to heavy machinery such as earth Management Branch, Alice moving equipment, road graders etc. Springs] 2007, pers. comm.
www.nt.gov.au/weeds 18 Athel pine Tamarix aphylla
References Berry, W. L. (1970). Characteristics of salts secreted by Tamarix aphylla. American Journal of Botany 57: 1226-1230. Brock, J. H. (1994). Tamarix spp. (Salt Cedar), as an invasive exotic Woody plant in arid and semi-arid riparian habitats of western USA. In: Ecology and Management of Invasive Riverside plants. (eds.) L. C. de Waal, et al. pp·27-44. John Wiley and Sons. Burbidge, A. A., Johnson, K. A., Fuller, P. J. & Southgate, R. I. (1988). Aboriginal knowledge of the mammals of the central deserts of Australia. Australian Wildlife Research, 15, 9-39. CAB International (2000). Forestry Compendium Global module. CAB International, Wallingford, UK CAB International (2006). Forestry Compendium. CAB International http://www.cabicompendium.org/fc/datasheet.asp?CCODE=TAA_AP&COUNTRY=0. Accessed 10/05/2006. Commonwealth Department of Environment and Heritage (2003). Athel pine (Tamarix aphylla). http://www.deh.gov.au/biodiversity/invasive/publications/pubs/t-aphylla.pdf. Accessed 10/03/2006. Csurhes, S. & Edwards, R. (1998). Potential Environmental Weeds in Australia: Candidate species for preventaive control. Queensland Department of Natural Resources, Brisbane. Csurhes, S. (2008). Pest plant risk assessment: Athel pine Tamarix spp. Queensland Department of Primary Industry and Fisheries, Brisbane. Department of Land Resource Management (2014). Draft Weed Management Plan for Athel pine (Tamarix aphylla) 2014, Department of Land Resource Management, Darwin. Dudley, T. (2004). Plant assessment: Tamarix aphylla (L.) Karsten. California invasive plant council, http://portal.calipc.org/files/PAFs/Tamarix%20aphylla.pdf. Duguid, A., Barnetson, J., Clifford, B., Pavey, C., Albrecht, D., Risler, J. & McNellie, M. (2002). Wetlands in the arid Northern Territory. A report to the Australian Government Department of the Environment and Heritage on the inventory and significance of wetlands in the arid NT. Northern Territory Government Department of Natural Resources, Environment and the Arts, Alice springs. Fuller, M. R. (1993b). The Invasion and Control of Tamarix aphylla on the Finke River, Central Australia. In: Proceedings of the 10th Australian Weeds Conference/14th Asian-Pacific Weed Science Society Conference, pp. 44-46, Weed Society of Queensland, Brisbane. Griffin, G. F., Stafford Smith, D. M., Morton, S. R., Allan, G. E., Masters, K. A. & Preece, N. J. (1989). Status and implications of the invasion of Tamarisk (Tamarix aphylla ) on the Finke River, Northern Territory, Australia. Journal of Environmental Management, 29, 297-315. Humphries, S., Groves, R. & Mitchell, D. (1991). Plant Invasions of Australian Ecosystems: A Status Review and Management Directions. Australian National Parks and Wildlife Service, Canberra. Kerle, J., Foulkes, J., Kimber, R. & Papenfus, D. (1992). The decline of the Brushtail Possum, Trichosurus vulpecula (Kerr 1798), in arid Australia. The Rangeland Journal, 14, 107-127. Litwak, M. (1957). The influence of T. aphylla on soil composition in the northern Negev of Israel. Bulletin of Resources Council of Israel 6D: 38-45. National Academy of Sciences (1980). Firewood crops; shrubs and tree spcies for energy production, Vol 1. National Academy of Sciences, Washington DC. Parsons, W. T. & Cuthbertson, E. G. (1992). Tamarisk, athel pine. In: Noxious Weeds of Australia. pp 620- 622. Inkarta Pres, Sydney. Pavey, C. (2006). Threatened species of the Northern Territory: Common Brushtail Possum (Central Australian population) Trichosurus vulpecula vulpecula. Northern Territory Government, Darwin, viewed 02/10/2012,
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